Additional file 1 of Bayesian spatio-temporal analysis of malaria prevalence in children between 2 and 10 years of age in Gabon

Additional file 1. Modelling details

Antibody titers against the three vaccine strains at baseline (day 0), day 28 and day 84.

<p>Red lines indicate the mean of all volunteers of the antihelminthic treated group (AT) and blue lines indicate the mean of all participants of the placebo group. Dashed lines indicate antibody titers of each participant.</p

Study profile.

<p>⁺Patients were excluded, because of infection with <i>S</i>. <i>haematobium</i>. *Participants not terminating the study are summarized as lost to follow up (n = 16).</p

Vaccine-specific IgG ASCs at day 0 and day 84, in antihelminthic treated (AT) and placebo group.

<p>Red and blue represent antihelminthic treated (AT) and control group.</p

Differences of HI titers between the respective visits (day 28, day 84) and day 0 (baseline).

<p>Red and blue colors represent the pre-treated (AT) and control group.</p

Vaccine specific IgA at day 0, day 28 and day 84 in antihelminthic treated (AT) (red) and placebo group (blue).

<p>Vaccine specific IgA at day 0, day 28 and day 84 in antihelminthic treated (AT) (red) and placebo group (blue).</p

Baseline characteristics and helminth infection at day -28.

<p>Baseline characteristics and helminth infection at day -28.</p

<i>Schistosoma haematobium</i> effects on <i>Plasmodium falciparum</i> infection modified by soil-transmitted helminths in school-age children living in rural areas of Gabon

<div><p>Background</p><p>Malaria burden remains high in the sub-Saharan region where helminths are prevalent and where children are often infected with both types of parasites. Although the effect of helminths on malaria infection is evident, the impact of these co-infections is not clearly elucidated yet and the scarce findings are conflicting. In this study, we investigated the effect of schistosomiasis, considering soil-transmitted helminths (STH), on prevalence and incidence of <i>Plasmodium falciparum</i> infection.</p><p>Methodology</p><p>This longitudinal survey was conducted in school-age children living in two rural communities in the vicinity of Lambaréné, Gabon. Thick blood smear light microscopy, urine filtration and the Kato-Katz technique were performed to detect malaria parasites, <i>S</i>. <i>haematobium</i> eggs and, STH eggs, respectively. <i>P</i>. <i>falciparum</i> carriage was assessed at inclusion, and incidence of malaria and time to the first malaria event were recorded in correlation with Schistosoma carriage status. Stratified multivariate analysis using generalized linear model was used to assess the risk of plasmodium infection considering interaction with STH, and survival analysis to assess time to malaria.</p><p>Main findings</p><p>The overall prevalence on subject enrolment was 30%, 23% and 9% for <i>S</i>. <i>haematobium</i>, <i>P</i>. <i>falciparum</i> infections and co-infection with both parasites, respectively. Our results showed that schistosomiasis in children tends to increase the risk of plasmodium infection but a combined effect with <i>Trichuris trichiura</i> or hookworm infection clearly increase the risk (aOR = 3.9 [_95%CI: 1.7–9.2]). The incidence of malaria over time was 0.51[_95%CI: 0.45–0.57] per person-year and was higher in the Schistosoma-infected group compared to the non-infected group (0.61 <i>vs</i> 0.43, <i>p</i> = 0.02), with a significant delay of time-to first-malaria event only in children aged from 6 to 10-years-old infected with <i>Schistosoma haematobium</i>.</p><p>Conclusions</p><p>Our results suggest that STH enhance the risk for <i>P</i>. <i>falciparum</i> infection in schistosomiasis-positive children, and when infected, that schistosomiasis enhances susceptibility to developing malaria in young children but not in older children.</p></div

GMT of vaccine strain specific antibodies.

<p>GMT of vaccine strain specific antibodies.</p

Exploratory analysis of the urine samples of volunteers at baseline.

A, B and C show the score plots of PCA model according to sex (male and female), anthelmintic pre-treatment (yes or no) and area of residence (location = rural or semi-urban) respectively. PCA model built for the two first component cover 26% of the variance and 6 components were required to cover 50% of the variance. D- is a cross-validated score plot of 2 class PLS-DA model with location as class identity. Model metrics: R2X = 0.232, R2Y = 0.81, Q2 = 0.40.</p